WiFi backoff timer

ABSTRACT

A communication device maintains a first backoff timer that corresponds to a first channel segment in a first radio frequency (RF) band, and maintains a second backoff timer that corresponds to a second channel segment in a second RF band. The first backoff timer is for determining when the communication device can transmit via the first channel segment, and the second backoff timer is for determining when the communication device can transmit via the second channel segment. In response to the first backoff timer expiring, the communication device waits to transmit via the first channel segment until the second backoff timer expires. After waiting to transmit via the first channel segment and in response to the second backoff timer expiring, the communication device transmits via the first channel segment beginning at a start time, and transmits via the second channel segment beginning at the start time.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/406,898 (now U.S. Pat. No. 10,939,476), entitled “WIFI BackoffTimer,” filed on May 8, 2019, which claims the benefit of U.S.Provisional Patent Application No. 62/668,699, entitled “Backoff withSwitched Primary Channel or Multiple Primary 20 MHz Channels,” filed onMay 8, 2018. Both of the applications referenced above are herebyincorporated herein by reference in their entireties.

Additionally, this application is related to U.S. patent applicationSer. No. 16/162,113 (now U.S. Pat. No. 10,805,051), entitled “WiFiChannel Aggregation” and filed on Oct. 16, 2018, and U.S. applicationSer. No. 16/179,634 (now U.S. Pat. No. 10,834,639), entitled “WiFiOperation with Channel Aggregation” and filed on Nov. 2, 2018, which arehereby incorporated by reference in their entireties.

FIELD OF TECHNOLOGY

The present disclosure relates generally to wireless communicationsystems, and more particularly to media access channel (MAC) support fordata transmission and reception over multiple communication channels.

BACKGROUND

Wireless local area networks (WLANs) have evolved rapidly over the pastdecade, and development of WLAN standards such as the Institute forElectrical and Electronics Engineers (IEEE) 802.11 Standard family hasimproved single-user peak data throughput. For example, the IEEE 802.11bStandard specifies a single-user peak throughput of 11 megabits persecond (Mbps), the IEEE 802.11a and 802.11g Standards specify asingle-user peak throughput of 54 Mbps, the IEEE 802.11n Standardspecifies a single-user peak throughput of 600 Mbps, and the IEEE802.11ac Standard specifies a single-user peak throughput in thegigabits per second (Gbps) range. Future standards promise to provideeven greater throughput, such as throughputs in the tens of Gbps range.

WLAN communication devices often utilize backoff timers to reduce alikelihood that a first WLAN communication device attempts to transmiton a WLAN communication channel while a second WLAN communication deviceis already transmitting on the same WLAN communication channel. Forexample, the first WLAN communication device sets a network allocationvector (NAV) based on a NAV indication or duration indication in aphysical layer (PHY) protocol data unit (PPDU) that is transmitted bythe second WLAN communication device. In some scenarios, the first WLANcommunication device does not receive the PPDU and cannot reliably setthe NAV for the WLAN communication channel to avoid interference withthe second WLAN communication device.

SUMMARY

In an embodiment, a method is for simultaneously transmitting via aplurality of channel segments that includes i) a first channel segmentin a first radio frequency (RF) band, and ii) a second channel segmentin a second RF band. The method includes: maintaining, at acommunication device, a first backoff timer that corresponds to thefirst channel segment, the first backoff timer for determining when thecommunication device can transmit via the first channel segment;maintaining, at the communication device, a second backoff timer thatcorresponds to the second channel segment, the second backoff timer fordetermining when the communication device can transmit via the secondchannel segment; in response to the first backoff timer expiring,waiting, by the communication device, to transmit via the first channelsegment until the second backoff timer expires; and after waiting totransmit via the first channel segment and in response to the secondbackoff timer expiring: transmitting, by the communication device, viathe first channel segment beginning at a start time, and transmitting,by the communication device, via the second channel segment beginning atthe start time.

In another embodiment, an apparatus comprises: a wireless networkinterface device that is configured to communicate simultaneously via aplurality of channel segments having i) a first channel segment in afirst RF band, and ii) a second channel segment in a second RF band. Thewireless network interface device comprises: one or more integratedcircuit (IC) devices; a first backoff timer that corresponds to thefirst channel segment, the first backoff timer implemented on the one ormore IC devices; and a second backoff timer that corresponds to thesecond channel segment, the second backoff timer implemented on the oneor more IC devices. The one or more IC devices are configured to:maintain the first backoff timer to determine when the communicationdevice can transmit via the first channel segment; maintain the secondbackoff timer to determine when the communication device can transmitvia the second channel segment; in response to the first backoff timerexpiring, control the wireless network interface device to wait totransmit via the first channel segment until the second backoff timerexpires; and after controlling the wireless network interface device towait to transmit via the first channel segment and in response to thesecond backoff timer expiring: control the wireless network interfacedevice to transmit via the first channel segment beginning at a starttime, and control the wireless network interface device to transmit viathe second channel segment beginning at the start time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example wireless local area network(WLAN), according to an embodiment.

FIG. 2A is a block diagram of an example physical layer (PHY) data unit,according to an embodiment;

FIG. 2B is a block diagram of an example preamble of a PHY data unit,according to an embodiment;

FIG. 3A is a diagram of an example system architecture corresponding toa communication device configured for multi-channel operation, accordingto an embodiment;

FIG. 3B is a diagram of an example system architecture corresponding toa communication device configured for multi-channel operation, accordingto another embodiment;

FIG. 4A is a diagram of an example operating channel at a first time,according to an embodiment;

FIG. 4B is a diagram of the example operating channel of FIG. 4A at asecond time, according to another embodiment;

FIG. 5 is an example timing diagram of a backoff timer synchronizationafter a primary channel change in an operating channel, in anembodiment.

FIG. 6A and FIG. 6B are example timing diagrams for a WLAN communicationdevice configured to use separate backoff timers in multiple componentchannels of a WLAN communication channel, in an embodiment.

FIG. 7 is an example timing diagrams for a WLAN communication deviceconfigured to use separate backoff timers in multiple component channelsof a WLAN communication channel, in an embodiment.

FIG. 8 is an example timing diagram for a WLAN communication deviceconfigured to suspend a backoff timer, in an embodiment.

FIG. 9 is an example timing diagram for a WLAN communication deviceconfigured to simultaneously utilize multiple primary channels, in anembodiment.

FIG. 10 is a flow diagram illustrating an example method for operationof a first communication device in a WLAN communication channel betweenthe first communication device and one or more second communicationdevices, according to an embodiment.

FIG. 11 is a flow diagram illustrating another example method foroperation of a first communication device in a WLAN communicationchannel between the first communication device and one or more secondcommunication devices, according to an embodiment.

FIG. 12 is a flow diagram illustrating yet another example method foroperation of a first communication device in a WLAN communicationchannel between the first communication device and one or more secondcommunication devices, according to an embodiment.

DETAILED DESCRIPTION

Multi-channel communication techniques described below are discussedmerely for explanatory purposes in the context of wireless local areanetworks (WLANs) that utilize protocols which are the same as or similarto protocols that are defined by the 802.11 Standard from the Instituteof Electrical and Electronics Engineers (IEEE) merely for explanatorypurposes. In other embodiments, however, multi-channel communicationtechniques are utilized in other types of suitable wirelesscommunication systems.

In various embodiments, a WLAN communication channel includes aplurality of component channels that are arranged in one or more channelsegments. In some embodiments, the channel segments are contiguous,while in other embodiments the channel segments are non-contiguous, inother words, separated by a frequency gap. In an embodiment, the channelsegments are located in different bands, for example, 2.4 GHz, 5 GHz,and 6 GHz bands. In other embodiments, other suitable bands are utilized(e.g., 60 GHz, “sub-1 GHz” or 900 MHz, 3.6 GHz, 4.9 GHz, etc.). Invarious embodiments, the component channels occupy a 20 MHz bandwidth,40 MHz bandwidth, 5 MHz bandwidth, or other suitable bandwidth withinthe corresponding band. In various embodiments, the channel segmentsinclude one or more component channels and have a total bandwidth of 20MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, or another suitable totalbandwidth.

In various embodiments, a WLAN communication device, for example, anaccess point (AP), designates the component channels of the WLANcommunication channel as “primary” channels or “secondary” channels. TheAP utilizes primary channels for various operations, such as fortransmission of various management transmissions (e.g., transmissionsassociated with association of a client station 154 with the AP 114,beacon transmissions by the AP 114, operating channel bandwidths switchannouncement transmissions, etc.), for conducting clear channelassessment (CCA) procedures, etc. The AP utilizes the primary and/orsecondary channels for packet transfers with other WLAN communicationdevices (e.g., transferring user data to client stations). In anembodiment, the AP generally reserves the primary channel(s) formanagement operations associated with the WLAN 110 and does not use thesecondary channels for the management operations.

In an embodiment, the WLAN communication channel has only one componentchannel designated as a primary channel, with remaining componentchannels designated as secondary channels. In another embodiment, theWLAN communication channel has two or more primary channels, withremaining component channels designated as secondary channels. In someembodiments, at least some of the two or more primary channels are indifferent bands. For example, a first primary channel is located in the5 GHz band and a second primary channels is located in the 6 GHz band.

In some embodiments, the AP changes the primary channel from a firstcomponent channel to a second component channel. In an embodiment, forexample, an AP provides an operating channel for a basic service set(BSS operating channel) for client stations that cannot concurrentlyutilize the entire BSS operating channel, e.g. the AP provides a 160 MHzBSS operating channel while at least some client stations only supportan 80 MHz operating channel. The client stations communicate indifferent segments of the BSS operating channel (e.g., different 80 MHzsegments) and the AP switches the primary channel to serve the clientstations communicating in the different segments. In another embodiment,the client station is configured to switch its primary channel.

Before transmitting a media access control protocol data unit (MPDU) viaa WLAN communication channel, a first WLAN communication device performsa backoff procedure that includes waiting for an expiration of a backofftimer that corresponds to the primary channel of the WLAN communicationchannel. In some scenarios, for instance, when switching primarychannels, a second WLAN communication device is in the midst of atransmission opportunity (TXOP) and is using (or has reserved) a samecomponent channel to which the primary channel of the first WLANcommunication device is to be changed. In some scenarios, the first WLANcommunication device may not be able to properly determine whether thecomponent channel is idle or unreserved based on a carrier sensemultiple access (CSMA) procedure, for example, when the second WLANcommunication device is receiving from a third, “hidden node” WLANcommunication device, or when the second WLAN communication device iswaiting before transmitting a packet within its TXOP. In thesescenarios, the first WLAN communication device may switch its primarychannel to the component channel, fail to detect the TXOP of the secondWLAN communication device, and begin a transmission that interferes withthe TXOP of the second WLAN communication device. In variousembodiments, when the primary channel is changed, the AP synchronizes anetwork allocation vector (NAV) for the component channel that is thenew primary channel with other WLAN communication devices that use thecomponent channel, in various embodiments. In an embodiment, forexample, the AP starts a NAV synchronization timer and postponesstarting the backoff timer until after expiration of the NAVsynchronization timer. In some scenarios, the additional “waiting” timeof the NAV synchronization timer reduces the likelihood that the AP willattempt to transmit on the new primary channel during the TXOP ofanother WLAN communication device.

FIG. 1 is a block diagram of an example wireless local area network(WLAN) 110, according to an embodiment. The WLAN 110 includes an accesspoint (AP) 114 that comprises a host processor 118 coupled to a networkinterface device 122. The network interface device 122 includes one ormore medium access control (MAC) processors 126 (sometimes referred toherein as “the MAC processor 126” for brevity) and one or more physicallayer (PHY) processors 130 (sometimes referred to herein as “the PHYprocessor 130” for brevity). The PHY processor 130 includes a pluralityof transceivers 134, and the transceivers 134 are coupled to a pluralityof antennas 138. Although three transceivers 134 and three antennas 138are illustrated in FIG. 1 , the AP 114 includes other suitable numbers(e.g., 1, 2, 4, 5, etc.) of transceivers 134 and antennas 138 in otherembodiments. In some embodiments, the AP 114 includes a higher number ofantennas 138 than transceivers 134, and antenna switching techniques areutilized.

The network interface device 122 is implemented using one or moreintegrated circuits (ICs) configured to operate as discussed below. Forexample, the MAC processor 126 is implemented, at least partially, on afirst IC, and the PHY processor 130 is implemented, at least partially,on a second IC, in various embodiments. As another example, at least aportion of the MAC processor 126 and at least a portion of the PHYprocessor 130 are implemented on a single IC. For instance, the networkinterface device 122 is implemented using a system on a chip (SoC),where the SoC includes at least a portion of the MAC processor 126 andat least a portion of the PHY processor 130.

In an embodiment, the host processor 118 includes a processor configuredto execute machine readable instructions stored in a memory device (notshown) such as a random access memory (RAM), a read-only memory (ROM), aflash memory, etc. In an embodiment, the host processor 118 isimplemented, at least partially, on a first IC, and the network device122 is implemented, at least partially, on a second IC, in variousembodiments. As another example, the host processor 118 and at least aportion of the network interface device 122 is implemented on a singleIC.

In various embodiments, the MAC processor 126 and/or the PHY processor130 of the AP 114 are configured to generate data units, and processreceived data units, that conform to a WLAN communication protocol suchas a communication protocol conforming to the IEEE 802.11 Standard oranother suitable wireless communication protocol. For example, the MACprocessor 126 is configured to implement MAC layer functions, includingMAC layer functions of the WLAN communication protocol, and the PHYprocessor 130 is configured to implement PHY functions, including PHYfunctions of the WLAN communication protocol. For instance, the MACprocessor 126 is configured to generate MAC layer data units such as MACservice data units (MSDUs), MAC protocol data units (MPDUs), etc., andprovide the MAC layer data units to the PHY processor 130. The PHYprocessor 130 is configured to receive MAC layer data units from the MACprocessor 126 and encapsulate the MAC layer data units to generate PHYdata units such as PHY protocol data units (PPDUs) for transmission viathe antennas 138. Similarly, the PHY processor 130 is configured toreceive PHY data units that were received via the antennas 138, andextract MAC layer data units encapsulated within the PHY data units. ThePHY processor 130 may provide the extracted MAC layer data units to theMAC processor 126, which processes the MAC layer data units.

PHY data units are sometimes referred to herein as “packets,” and MAClayer data units are sometimes referred to herein as “frames.”

In connection with generating one or more radio frequency (RF) signalsfor transmission, the PHY processor 130 is configured to process (whichmay include modulating, filtering, etc.) data corresponding to a PPDU togenerate one or more digital baseband signals, and convert the digitalbaseband signal(s) to one or more analog baseband signals, according toan embodiment. Additionally, the PHY processor 130 is configured toupconvert the one or more analog baseband signals to one or more RFsignals for transmission via the one or more antennas 138.

In connection with receiving one or more RF signals, the PHY processor130 is configured to downconvert the one or more RF signals to one ormore analog baseband signals, and to convert the one or more analogbaseband signals to one or more digital baseband signals. The PHYprocessor 130 is further configured to process (which may includedemodulating, filtering, etc.) the one or more digital baseband signalsto generate a PPDU.

The PHY processor 130 includes amplifiers (e.g., a low noise amplifier(LNA), a power amplifier, etc.), a radio frequency (RF) downconverter,an RF upconverter, a plurality of filters, one or more analog-to-digitalconverters (ADCs), one or more digital-to-analog converters (DACs), oneor more discrete Fourier transform (DFT) calculators (e.g., a fastFourier transform (FFT) calculator), one or more inverse discreteFourier transform (IDFT) calculators (e.g., an inverse fast Fouriertransform (IFFT) calculator), one or more modulators, one or moredemodulators, etc.

The PHY processor 130 is configured to generate one or more RF signalsthat are provided to the one or more antennas 138. The PHY processor 130is also configured to receive one or more RF signals from the one ormore antennas 138.

The MAC processor 126 is configured to control the PHY processor 130 togenerate one or more RF signals by, for example, providing one or moreMAC layer data units (e.g., MPDUs) to the PHY processor 130, andoptionally providing one or more control signals to the PHY processor130, according to some embodiments. In an embodiment, the MAC processor126 includes a processor configured to execute machine readableinstructions stored in a memory device (not shown) such as a RAM, a readROM, a flash memory, etc., to provide at least some of the functionalitydescribed herein. In another embodiment, the MAC processor 126 includesa hardware state machine that provides at least some of thefunctionality described herein.

In various embodiments, the MAC processor 126 includes one or moremulti-band backoff timers 127 configured to perform one or more backoffprocedures in connection with multiple communication channels inmultiple RF bands. The backoff procedure involves waiting a period oftime before attempting to use a communication channel, according to anembodiment. In an embodiment, the multi-band backoff timers 127 includeone or more network allocation vector (NAV) counters for monitoring useof multiple communication channels in multiple RF bands, according to anembodiment. For example, when the access point 114 receives a packet,the MAC processor 126 sets a NAV counter according to a value in aduration field in a MAC header of the packet, at least in somesituations, according to an embodiment. The MAC processor 126 monitorsthe NAV counter to determine when the transmission of the packet hasended. Some packets are configured for reserving a channel for a desiredtime period and the duration field in the MAC header of the packet isset to the desired time period. When receiving such a packet, the MACprocessor 126 sets a NAV counter according to the value in the durationfield in a MAC header of the packet. The MAC processor 126 monitors theNAV counter to determine when the reservation of the channel has ended.In some embodiments, the MAC processor 126 includes i) one or more NAVcounters, and ii) one or more NAV synchronization timers that allow forsynchronization after a primary channel change in an operating channel,as described below.

In an embodiment, the MAC processor 126 and the PHY processor 130 areconfigured to operate according to a first WLAN communication protocol(e.g., an IEEE 802.11be Standard, or extremely high throughput (EHT)),and also according to one or more second WLAN communication protocols(e.g., as defined by one or more of the IEEE 802.11n Standard, IEEE802.11ac Standard, the IEEE 802.11ax Standard and/or other suitable WLANcommunication protocols) that are legacy protocols with respect to thefirst WLAN communication protocol. The one or more second WLANcommunication protocols are sometimes collectively referred to herein asa “legacy WLAN communication protocol” or simply “legacy protocol.”

The WLAN 110 includes a plurality of client stations 154. Although threeclient stations 154 are illustrated in FIG. 1 , the WLAN 110 includesother suitable numbers (e.g., 1, 2, 4, 5, 6, etc.) of client stations154 in various embodiments. The client station 154 includes a hostprocessor 158 coupled to a network interface device 162. The networkinterface device 162 includes one or more MAC processors 166 (sometimesreferred to herein as “the MAC processor 166” for brevity) and one ormore PHY processors 170 (sometimes referred to herein as “the PHYprocessor 170” for brevity). The PHY processor 170 includes a pluralityof transceivers 174, and the transceivers 174 are coupled to a pluralityof antennas 178. Although three transceivers 174 and three antennas 178are illustrated in FIG. 1 , the client station 154 includes othersuitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers 174 andantennas 178 in other embodiments. In some embodiments, the clientstation 154 includes a higher number of antennas 178 than transceivers174, and antenna switching techniques are utilized.

The network interface device 162 is implemented using one or more ICsconfigured to operate as discussed below. For example, the MAC processor166 is implemented on at least a first IC, and the PHY processor 170 isimplemented on at least a second IC, in various embodiments. As anotherexample, at least a portion of the MAC processor 166 and at least aportion of the PHY processor 170 is implemented on a single IC. Forinstance, the network interface device 162 is implemented using an SoC,where the SoC includes at least a portion of the MAC processor 166 andat least a portion of the PHY processor 170.

In an embodiment, the host processor 158 includes a processor configuredto execute machine readable instructions stored in a memory device (notshown) such as a RAM, a ROM, a flash memory, etc. In an embodiment, thehost processor 158 is implemented, at least partially, on a first IC,and the network device 162 is implemented, at least partially, on asecond IC, in various embodiments. As another example, the hostprocessor 158 and at least a portion of the network interface device 162is implemented on a single IC.

In various embodiments, the MAC processor 166 and the PHY processor 170of the client device 154 are configured to generate data units, andprocess received data units, that conform to the WLAN communicationprotocol or another suitable communication protocol. For example, theMAC processor 166 is configured to implement MAC layer functions,including MAC layer functions of the WLAN communication protocol, andthe PHY processor 170 is configured to implement PHY functions,including PHY functions of the WLAN communication protocol. The MACprocessor 166 is configured to generate MAC layer data units such asMSDUs, MPDUs, etc., and provide the MAC layer data units to the PHYprocessor 170. The PHY processor 170 is configured to receive MAC layerdata units from the MAC processor 166 and encapsulate the MAC layer dataunits to generate PHY data units such as PPDUs for transmission via theantennas 178. Similarly, the PHY processor 170 is configured to receivePHY data units that were received via the antennas 178, and extract MAClayer data units encapsulated within the PHY data units. The PHYprocessor 170 may provide the extracted MAC layer data units to the MACprocessor 166, which processes the MAC layer data units.

The PHY processor 170 is configured to downconvert one or more RFsignals received via the one or more antennas 178 to one or morebaseband analog signals, and convert the analog baseband signal(s) toone or more digital baseband signals, according to an embodiment. ThePHY processor 170 is further configured to process the one or moredigital baseband signals to demodulate the one or more digital basebandsignals and to generate a PPDU. The PHY processor 170 includesamplifiers (e.g., an LNA, a power amplifier, etc.), an RF downconverter,an RF upconverter, a plurality of filters, one or more ADCs, one or moreDACs, one or more DFT calculators (e.g., an FFT calculator), one or moreIDFT calculators (e.g., an IFFT calculator), one or more modulators, oneor more demodulators, etc.

The PHY processor 170 is configured to generate one or more RF signalsthat are provided to the one or more antennas 178. The PHY processor 170is also configured to receive one or more RF signals from the one ormore antennas 178.

The MAC processor 166 is configured to control the PHY processor 170 togenerate one or more RF signals by, for example, providing one or moreMAC layer data units (e.g., MPDUs) to the PHY processor 170, andoptionally providing one or more control signals to the PHY processor170, according to some embodiments. In an embodiment, the MAC processor166 includes a processor configured to execute machine readableinstructions stored in a memory device (not shown) such as a RAM, a ROM,a flash memory, etc. to provide at least some of the functionalitydescribed herein. In an embodiment, the MAC processor 166 includes ahardware state machine that provides at least some of the functionalitydescribed herein.

In an embodiment, the MAC processor 166 and the PHY processor 170 areconfigured to operate according to the first WLAN communicationprotocol, and also according to the legacy WLAN communication protocol.

In an embodiment, each of the client stations 154-2 and 154-3 has astructure that is the same as or similar to the client station 154-1.Each of the client stations 154-2 and 154-3 has the same or a differentnumber of transceivers and antennas. For example, the client station154-2 and/or the client station 154-3 each have only two transceiversand two antennas (not shown), according to an embodiment.

In an embodiment, one or both of the client stations 154-2 and 154-3 areconfigured to operate according to the legacy WLAN communicationprotocol, but not according to the first WLAN communication protocol.Such client stations are referred to herein as “legacy client stations.”Similarly, an access point that is similar to the AP 114 and isconfigured to operate according to the legacy WLAN communicationprotocol, but not according to the first WLAN communication protocol, isreferred to herein as a “legacy AP.” More generally, wirelesscommunication devices that are configured to operate according to thelegacy WLAN communication protocol, but not according to the first WLANcommunication protocol, are referred to herein as a “legacycommunication devices.”

FIG. 2A is a diagram of an example PPDU 200 that the network interfacedevice 122 (FIG. 1 ) is configured to generate and transmit to one ormore client stations 154 (e.g., the client station 154-1), according toan embodiment. The network interface device 162 (FIG. 1 ) may also beconfigured to transmit data units the same as or similar to the PPDU 200to the AP 114. The PPDU 200 may occupy a 20 MHz bandwidth or anothersuitable bandwidth. Data units similar to the PPDU 200 occupy othersuitable bandwidth such as 40 MHz, 60 MHz, 80 MHz, 100 MHz, 120 MHz, 140MHz, 160 MHz, 180 MHz, 200 MHz, etc., for example, or other suitablebandwidths, in other embodiments.

The PPDU 200 includes a PHY preamble 204 and a PHY data portion 208. ThePHY preamble 204 may include at least one of a legacy portion 212 and anon-legacy portion 216, in at least some embodiments. In an embodiment,the legacy portion 212 is configured to be processed by legacycommunication devices in the WLAN 110 (i.e., communication devices thatoperate according to a legacy communication protocol), enabling thelegacy communication devices to detect the PPDU 200 and to obtain PHYinformation corresponding to the PPDU 200, such as a duration of thePPDU 200.

FIG. 2B is a diagram of an example PHY preamble 220. In an embodiment,the PHY preamble 220 corresponds to the PHY preamble 204. In anembodiment, the PHY preamble 220 is included in the legacy portion 212.In another embodiment, the PHY preamble 220 is included in thenon-legacy portion 216. The PHY preamble 220 includes one or more shorttraining fields (STFs) 224, one or more long training field (LTFs) 228,and one or more signal fields (SIGs) 232. In an embodiment, the STFs 224and the LTFs 228 are used for packet detection, automatic gain control(AGC), frequency offset estimation, channel estimation, etc. In anembodiment, the number of LTFs in the LTFs 228 correspond to a number ofspatial/space-time streams used for transmission of the PPDU 200. In anembodiment, the SIGs 232 are used to signal PHY communication parameters(e.g., a modulation and coding scheme (MCS), a number of spatialstreams, a frequency bandwidth, etc.) corresponding to the PPDU 200.

In some embodiments, the PHY preamble 220 omits one or more of thefields 224-232. In some embodiments, the PHY preamble 220 includes oneor more additional fields not illustrated in FIG. 2B. In someembodiments, the order of the fields 224-232 is different thanillustrated in FIG. 2B. In an embodiment, the PPDU 200 is generated andtransmitted as a sequence of orthogonal frequency division multiplexing(OFDM) symbols. In an embodiment, each of the STF 224, the LTF 228, theSIG 232, and the data portion 208 comprises one or more OFDM symbols.

In an embodiment, the AP 114 and a plurality of client stations 154 areconfigured for multiple user (MU) communication using orthogonalfrequency division multiple access (OFDMA) transmissions. In anembodiment, the PPDU 200 is an MU OFDMA data unit in which independentdata streams are transmitted to or by multiple client stations 154 usingrespective sets of OFDM tones allocated to the client stations 154. Forexample, in an embodiment, available OFDM tones (e.g., OFDM tones thatare not used as DC tones and/or guard tones) are segmented into multipleresource units (RUs), and each of the multiple RUs is allocated to datato one or more client stations 154. In an embodiment, the independentdata streams in respective allocated RUs are further transmitted usingrespective spatial streams, allocated to the client stations 154, usingmultiple-input multiple-output (MIMO) techniques. In an embodiment, thePPDU 200 is an MU-MIMO PHY data unit in which independent data streamsare transmitted to multiple client stations 154 using respective spatialstreams allocated to the client stations 154.

In an embodiment, an operating communication channel of a communicationdevice in the WLAN 110 is divided into a plurality of smaller componentchannels, each corresponding to a width of 20 MHz, or another suitablefrequency bandwidth. Multiple component channels are concatenated, or“bonded” to form a wider channel, in some embodiments. For instance, a40 MHz channel is formed by combining two 20 MHz component channels, an80 MHz channel is formed by combining two 40 MHz channels, and a 160 MHzchannel is formed by combining two 80 MHz channels, in variousembodiments. In an embodiment, the operating frequency band is dividedinto component channels of a width different than 20 MHz. In someembodiments, the component channels are aggregated, as described below.

In an embodiment, the PPDU 200 has a 20 MHz frequency bandwidth and istransmitted in a 20 MHz channel. In other embodiments, the PPDU 200 mayhave a frequency bandwidth of 40 MHz, 80 MHz, 100 MHz, 120 MHz, etc.,and is correspondingly transmitted over a 40 MHz, 80 MHz, 100 MHz, 120MHz, etc., channel, respectively. In some such embodiments, at least aportion of the PPDU 200 (e.g., at least a legacy portion of the PHYpreamble 204, or the entirety of the PHY preamble 204) is generated bygenerating a field corresponding to a 20 MHz component channel bandwidthand repeating the field over a number of 20 MHz component channelscorresponding to the transmission channel, in an embodiment. Forexample, in an embodiment in which the PPDU 200 occupies an 80 MHzchannel, at least the legacy portion 212 corresponding to the 20 MHzcomponent channel bandwidth is replicated in each of four 20 MHzcomponent channels that comprise the 80 MHz channel.

In an embodiment, one or more communication devices in the WLAN 110(e.g., the AP 114, the client station 154, etc.) are configured forvarious multi-channel operations. In an embodiment corresponding tomulti-channel operation, two or more communication channels (alsosometimes referred to herein as a “channel segments”) are aggregated toform an aggregate channel for simultaneous transmission or receptionover the two or more aggregated communication channels in the WLAN 110.For instance, in an embodiment, the AP 114 is configured to transmit afirst signal in a first communication channel segment (sometimesreferred to herein as “first channel segment”), and simultaneouslytransmit a second signal over a second channel segment (sometimesreferred to herein as “second channel segment”) where the first andsecond channel segments do not overlap. In some embodiments, the AP 114commences transmission of the first signal and the second signal at asame start time (e.g., synchronously), for example, using multiple RFradios, as described herein. In an embodiment, the AP 114 is configuredto cease transmission of the first signal and the second signal at asame end time. In an embodiment, the AP 114 is configured to ceasetransmission of the first signal and the second signal at different endtimes. In an embodiment, the AP 114 is configured to receive a firstsignal in a first channel segment and simultaneously receive a secondsignal over a second channel segment, wherein the first signal and thesecond signal have an identical start time. In an embodiment, the firstsignal and the second signal have identical end times. In anotherembodiment, the first signal and the second signal have different endtimes.

In an embodiment corresponding to multi-channel operation, the firstchannel segment and the second channel segment are non-contiguous, i.e.,there is a gap in frequency between the first channel segment and thesecond channel segment. In another embodiment, the first channel segmentand the second channel segment are contiguous, i.e., there is nofrequency gap between the first channel segment and the second channelsegment. In an embodiment, the first channel segment and the secondchannel segment are of different frequency bandwidths. In an embodiment,the first channel segment and the second channel segment consist ofrespective different numbers of component channels. In anotherembodiment, the first channel segment and the second channel segment areof a same bandwidth and consist of a same number of component channels.

In an embodiment, different communication devices (i.e., the AP 114 andthe client stations 154) are configured for operation in differentfrequency bands. In an embodiment, at least some communication devices(e.g., the AP 114 and the client station 154) in the WLAN 110 areconfigured for operation over multiple different frequency bands.Example frequency bands include, a first frequency band corresponding toa frequency range of approximately 2.4 GHz-2.5 GHz (“2 GHz band”), and asecond frequency band corresponding to a frequency range ofapproximately 5 GHz-5.9 GHz (“5 GHz band”) of the RF spectrum. In anembodiment, one or more communication devices within the WLAN may alsobe configured for operation in a third frequency band in the 6 GHz-7 GHzrange (“6 GHz band”). Each of the frequency bands comprises pluralcomponent channels which are, in some embodiments, combined within therespective frequency bands to generate channels of wider bandwidths, asdescribed above. In an embodiment corresponding to multi-channeloperation over multiple communication channel segments aggregated toform an aggregated communication channel, at least some of the multiplechannel segments are in different ones of multiple frequency bands, orthe multiple channel segments are within a same frequency band.

In an embodiment, the first WLAN communication protocol permits agreater variety of communication channel configurations than ispermitted by the legacy WLAN communication protocol. For example, thelegacy WLAN communication protocol permits certain combinations ofcomponent channels to form communication channels of certain bandwidths,whereas the first WLAN communication protocol permits additionalcomponent channel combinations in addition to the component channelcombinations permitted by the legacy WLAN communication protocol. Forexample, whereas the legacy WLAN communication protocol permitscontiguous bandwidths of 20 MHz, 40 MHz, 80 MHz, and 160 MHz and a splitfrequency bandwidth 80+80 MHz, the first WLAN communication protocoladditionally permits contiguous bandwidths of 60 MHz, 100 MHz, 120 MHz,140 MHz, and split frequency bandwidths of 20+20 MHz, 20+40 MHz, 20+80MHz, 40+40 MHz, 40+80 MHz, etc., in various embodiments.

In an embodiment, a communication device (e.g., the AP 114, the clientstation 154-1, etc.) configured to operate according to the first WLANcommunication protocol includes multiple RF radios, where respectiveones of the multiple RF radios transmit/receive signals in respective RFchannel segments of an aggregate communication channel. In someembodiments, the signals transmitted/received by respective ones of themultiple RF radios are synchronously transmitted/received in contiguousor non-contiguous channel segments. For example, a signaltransmitted/received in an 80 MHz-wide channel segment by a first RFradio and a signal in a 40 MHz-wide channel segment is synchronouslytransmitted/received by a second RF radio, where the 80 MHz-wide and the40 MHz-wide channel segments form a contiguous 120 MHz channel bandwidthin one embodiment, and form a non-contiguous 80+40 MHz channel bandwidthin another embodiment. In some embodiments, the signalstransmitted/received by respective ones of the multiple RF radios areasynchronously transmitted/received in the contiguous or non-contiguouschannel segments. In other words, signals transmitted or received by afirst RF radio do not need to be synchronized in time with signalstransmitted or received by a second RF radio. In an embodiment, forexample, a first RF radio of a communication device transmits a firstsignal while a second RF radio of the communication devicesimultaneously receives (or transmits) a second signal, where the secondRF radio begins transmitting or receiving the second signal after thefirst RF radio has begun transmitting the first RF signal (see, e.g.,FIG. 9 ).

FIG. 3A is a diagram of an example system architecture 300 correspondingto a communication device configured for multi-channel operation,according to an embodiment. For instance, in an embodiment, the systemarchitecture 300 is configured for transmission/reception overaggregated communication channel segments. In an embodiment, the systemarchitecture 300 corresponds to the AP 114. In another embodiment, thesystem architecture 300 corresponds to the client station 154-1. Invarious embodiments, the system architecture 300 is configured forsimultaneous transmission and/or reception over the aggregatedcommunication channel. In an embodiment, the system architecture 300 isconfigured for synchronous transmission and/or reception over theaggregated communication channel. In an embodiment, the systemarchitecture 300 is configured for asynchronous transmission and/orreception over the aggregated communication channel. In anotherembodiment, the system architecture is configured for both synchronousand asynchronous transmission and/or reception over the aggregatedcommunication channel.

In an embodiment, the system architecture 300 is configured foroperation over two communication channel segments and includes aforwarding processor 304. The communication device 300 also includes asingle MAC processor 308, a first PHY processor 316, and a second PHYprocessor 320. The single MAC processor 308 is coupled to the first PHYprocessor 316 and the second PHY processor 320. The single MAC processor308 exchanges frames with the first PHY processor 316 and the second PHYprocessor 320. In an embodiment, the MAC layer has an interface, forexample, a data service access point (SAP) interface, to a layer abovethe MAC layer (e.g., a logical link control layer or network layer inthe Open Systems Interconnection model). In another embodiment, theinterface (i.e., data SAP interface) between the MAC layer and the layerabove the MAC layer is integral with the MAC layer.

In an embodiment, the single MAC processor 308 corresponds to the MACprocessor 126 of FIG. 1 . In another embodiment, the single MACprocessor 308 corresponds to the MAC processor 166 of FIG. 1 . In anembodiment, the first PHY processor 316 and the second PHY processor 320correspond to the PHY processor 130 of FIG. 1 . In another embodiment,the first PHY processor 316 and the second PHY processor 320 correspondto the PHY processor 170 of FIG. 1 .

The first PHY processor 316 includes a first baseband signal processor324 (Baseband-1) coupled to a first RF radio 328 (Radio-1). The secondPHY processor 320 includes a second baseband signal processor 332(Baseband-2) coupled to a second RF radio 336 (Radio-2). In anembodiment, the RF radio 328 and the RF radio 336 correspond to thetransceivers 134 of FIG. 1 . In an embodiment, the RF radio 328 isconfigured to operate on a first RF band, and the RF radio 336 isconfigured to operate on a second RF band. In another embodiment, the RFradio 328 and the RF radio 336 are both configured to operate on thesame RF band.

In an embodiment, the MAC processor 308 generates and parses datacorresponding to MAC layer data units (e.g., frames) into a plurality ofdata streams corresponding to respective communication channel segments.In an embodiment, the frames can be transmitted in any channel segmentsdynamically, i.e., without a band switch negotiation. The MAC processor308 provides the parsed data streams to the Baseband-1 324 and theBaseband-2 332. The Baseband-1 324 and the Baseband-2 332 are configuredto receive the respective data streams from the MAC processor 308, andencapsulate and encode the respective data streams to generaterespective baseband signals corresponding to PPDUs. In an embodiment,the respective baseband signals have different bandwidths. TheBaseband-1 324 and the Baseband-2 332 provide the respective basebandsignals to the Radio-1 328 and the Radio-2 336. The Radio-1 328 andRadio-2 336 upconvert the respective baseband signals to generaterespective RF signals for transmission via the first channel segment andthe second channel segment, respectively. The Radio-1 328 transmits afirst RF signal via the first channel segment and the Radio-2 336transmits a second RF signal via a second channel segment.

The communication device 300 also includes synchronization controlcircuitry 340, in some embodiments. The synchronization controlcircuitry 340 is configured to ensure that respective transmittedsignals over the first channel segment and the second channel segmentare synchronized. The synchronization control circuitry 340 is coupledto the Baseband-1 324 and the Baseband-2 332 to ensure that therespective baseband signals are synchronized in time.

The Radio-1 328 and the Radio-2 336 are also configured to receiverespective RF signals via the first channel segment and the secondchannel segment, respectively. The Radio-1 328 and the Radio-2 336generate respective baseband signals corresponding to the respectivereceived signals. In an embodiment, the generated respective basebandsignals have different bandwidths. The generated respective basebandsignals are provided to the respective baseband signal processorsBaseband-1 324 and Baseband-2 332. The Baseband-1 324 and the Baseband-2332 generate respective data streams that are provided to the MACprocessor 308. The MAC processor 308 processes the respective datastreams. In an embodiment, the MAC processor 308 deparses the datastreams received from the Baseband-1 324 and the Baseband-2 332 into asingle information bit stream.

In an embodiment, the forwarding processor 304 is omitted and the MACprocessor 308 is coupled to another suitable processor (e.g., the hostprocessor 118 (FIG. 1 )) that performs one or more higher leveloperations corresponding to data transmission and reception. Forinstance, in an embodiment, the other processor performs one or moreoperations corresponding to Layer 3 and above as characterized in theOSI model.

FIG. 3B is a diagram of an example system architecture 350 correspondingto a communication device configured for multi-channel operation,according to another embodiment. For instance, in an embodiment, thesystem architecture 350 is configured for synchronous and/orasynchronous transmission/reception over aggregated communicationchannels. In an embodiment, the system architecture 350 corresponds tothe AP 114. In another embodiment, the system architecture 350corresponds to the client station 154-1.

The system architecture 350 is similar to the system architecture 300 ofFIG. 3A, and like-numbered elements are not discussed in detail forpurposes of brevity. The communication device 350 includes a single MACprocessor 358 coupled to a PHY processor 366. The single MAC processor308 exchanges frames with the PHY processor 366. In an embodiment, thesingle MAC processor 358 corresponds to the MAC processor 126 of FIG. 1. In another embodiment, the single MAC processor 358 corresponds to theMAC processor 166 of FIG. 1 . In an embodiment, the PHY processor 366corresponds to the PHY processor 130 of FIG. 1 . In another embodiment,the PHY processor 366 corresponds to the PHY processor 170 of FIG. 1 .The PHY processor 366 includes a single baseband signal processor 374.The single baseband signal processor 374 is coupled to the Radio-1 328and the Radio-2 336.

In an embodiment, the MAC processor 358 generates data corresponding toMAC layer data units (e.g., frames) and provides the frames to thebaseband signal processor 374. The baseband signal processor 374 isconfigured to receive frames from the MAC processor 358, and parse datacorresponding to the frames into a plurality of bit streams. Thebaseband signal processor 374 is also configured to encapsulate andencode the respective bit streams to generate respective basebandsignals corresponding to PPDUs. In an embodiment, the respectivebaseband signals have different bandwidths. The baseband signalprocessor 374 provides the respective baseband signals to the Radio-1328 and the Radio-2 336. The Radio-1 328 and Radio-2 336 upconvert therespective baseband signals to generate respective RF signals fortransmission via the first channel segment and the second channelsegment, respectively. The Radio-1 820 transmits a first RF signal viathe first channel segment and the Radio-2 336 transmits a second RFsignal via a second channel segment.

The baseband signal processor 374 is configured to ensure thatrespective transmitted signals over the first channel segment and thesecond channel segment are synchronized. For example, the basebandsignal processor 374 is configured to generate the respective basebandsignals such that the respective baseband signals are synchronized intime.

The Radio-1 328 and the Radio-2 336 are also configured to receiverespective RF signals via the first channel segment and the secondchannel segment, respectively. The Radio-1 328 and the Radio-2 336generate respective baseband signals corresponding to the respectivereceived signals. In an embodiment, the generated respective basebandsignals have different bandwidths. The generated respective basebandsignals are provided to the baseband signal processor 374. The basebandsignal processor 374 generate respective bit streams, and de-parse thebit streams into a data stream corresponding to frames. The basebandsignal processor 374 provides the frames to the MAC processor 358. TheMAC processor 358 processes the frames.

As discussed above, in an embodiment, an operating communication channelof a communication device in the WLAN 110 is divided into a plurality ofsmaller component channels. In an embodiment, at least one of thesmaller component channels is designated as a primary channel and theremaining component channels are secondary channels. In an embodiment,as described above, the primary channel is utilized for both managementtransmissions and data transmissions, while secondary channels are usedfor data transmissions but not management transmissions. A communicationdevice (e.g., the AP 114 or the client station 154-1) operating in theWLAN 110 utilizes the at least one smaller component channel that isdesignated as a primary channel for various operations, such as fortransmission of various management transmissions (e.g., transmissionsassociated with association of a client station 154 with the AP 114,beacon transmissions by the AP 114, operating channel bandwidths switchannouncement transmissions, etc.), for conducting clear channelassessment (CCA) procedures, etc. In an embodiment, an aggregateoperating channel of a communication device (e.g., the AP 114 or theclient station 154-1) includes multiple primary channels. For example,in an embodiment in which a first channel segment is aggregated with asecond channel segment to form an aggregated communication channel, afirst component channel in the first channel segment is designated as afirst primary channel of the aggregate communication channel and asecond component channel in the second channel segment is designated ina second primary channel of the aggregate communication channel. Inanother embodiment, an aggregate communication channel of acommunication device (e.g., the AP 114 or the client station 154-1)includes a single primary channel. For example, in an embodiment inwhich a first channel segment is aggregated with a second channelsegment form an aggregate communication channel, a component channel inone of the first channel segment and the second channel segment isdesignated as a primary channel of the aggregate communication channel.The other one of the first channel segment and the second channelsegment does not include a primary channel, in this embodiment.

FIG. 4A is a diagram of an example operating channel 400 at a firsttime, according to an embodiment. In an embodiment, the operatingchannel 400 corresponds to an operating channel of the AP 114, or of abasic service set (BSS) supported by the AP 114. In another embodiment,the operating channel 400 corresponds to an operating channel of aclient station 154 (e.g., the client station 154-1). In otherembodiments, the operating channel 400 is employed by a communicationdevice (e.g., an AP or a client station) in a suitable communicationnetwork different from the WLAN 110. An operating channel such as theoperating channel 400 that corresponds to an operating channel of an APor a BSS supported by the AP is sometimes referred to herein as an “APoperating channel” or a “BSS operating channel.” An operating channelsuch as the operating channel 400 that corresponds to an operatingchannel of a client station is sometimes referred to herein as an “STAoperating channel.” In the embodiment shown in FIG. 4A, the operatingchannel 400 corresponds to the AP 114 and a first client station STA1.

The operating channel 400 includes a first channel segment 410aggregated with a second channel segment 420. The first channel segment410 occupies a first frequency bandwidth and comprises a first number ofcomponent channels, and the second channel segment 420 occupies a secondfrequency bandwidth and comprises a second number of component channels.In various embodiments, the first bandwidth of the first channel segment410 and the second bandwidth of the second channel segment 420 are equalor are unequal. In various embodiments, the first number of componentchannels of the first channel segment 410 and the second number ofcomposite channels of the second channel segment 420 are equal or areunequal.

In an embodiment, the first channel segment 410 and the second channelsegment 420 are non-adjacent in frequency (e.g., are non-contiguous).For example, a gap in frequency exists between the first channel segment410 and the second first channel segment 420. In various embodiments,the gap is at least 500 kHz, at least 1 MHz, at least 5 MHz, at least 20MHz, etc. In some embodiments, the first channel segment 410 and thesecond channel segment 420 are located in different bands, for example,2.4 GHz, 5 GHz, and 6 GHz bands. In other embodiments, other suitablebands are utilized (e.g., 60 GHz, “sub-1 GHz” or 900 MHz, 3.6 GHz, 4.9GHz, etc.). In another embodiment, the first channel segment 410 and thesecond channel segment 420 are adjacent in frequency (e.g., contiguous).In this embodiment, there is no frequency gap between first channelsegment 410 and the second channel segment 420.

In an example embodiment, the first channel segment 410 has a bandwidthof 80 MHz and the second channel segment 420 has a bandwidth of 80 MHz.In an embodiment in which the first channel segment 410 and the secondchannel segment 420 are not adjacent in frequency, the operating channel400 is sometimes referred to as an 80+80 MHz channel. On the other hand,in an embodiment in which the first channel segment 410 and the secondchannel segment 420 are adjacent in frequency, the operating 400 issometimes referred to as 160 MHz channel. In general, communicationchannels similar to the operating channel 400 in which the first channelsegment and the second channel segment are not adjacent in frequency,the aggregate communication channel is referred to as (bandwidth of thefirst channel segment)+(bandwidth of the second channel segment)channel. On the other hand, communication channels similar to theoperating channel 400 in which the first channel segment and the secondchannel segment are adjacent in frequency, or in which the secondchannel segment 420 is omitted (i.e., the second channel segment 420 hasa bandwidth of 0 MHz), the aggregate communication channel 400 isreferred to as (the sum of the first channel segment bandwidth and thesecond channel segment bandwidth) channel. In an embodiment, validchannel configurations of the aggregate communication channel 400include: 20 MHz channel, 40 MHz channel, 60 MHz channel, 80 MHz channel,100 MHz, 120 MHz channel, 140 MHz channel, 160 MHz channel, 320 MHzchannel, 20+40 MHz channel, 20+80 MHz channel, 40+80 MHz channel, 20+160MHz, 40+320 MHz, and so on. In an embodiment, a respective bandwidth ofeach channel segment 410, 420 is selected from a set of possible channelbandwidths of 20 MHz, 40 MHz and 80 MHz. In other embodiments, othersuitable sets of possible bandwidths are utilized.

At the first time shown in FIG. 4A, the operating channel 400, includesa single primary channel. For example, the AP 114 designates a singlecomponent channel of the first channel segment 410 as a primary channel,in an embodiment. In the illustrated embodiment, a first componentchannel of the first channel segment 410 is designated as a firstprimary channel 412. In some embodiments, the operating channel 400includes more than two primary channels. For example, more than twocomponent channels of the operating channel 400 are designated asprimary channels, in some embodiments.

The operating channel 400 also includes secondary channels, in anembodiment. In an embodiment, the AP 114 designates each componentchannel of the first channel segment 410 and the second channel segment420 that is not designated as a primary channel as a secondary channel.In the illustrated embodiment, the first channel segment 410 includesthree secondary channels 414 and the second channel segment 420 includesthree secondary channels 424. In other embodiments, the first channelsegment 410 and/or the second channel segment 420 includes anothersuitable number (e.g., 0, 1, 2, 4, 5, etc.) of secondary channels 414,424. In some embodiments, the number of secondary channels 414 of thefirst channel segment 410 is not equal to the number of secondarychannels 424 of the second channel segment 420.

In some embodiments, the AP 114 generates one or more MAC data units toinclude i) a first primary channel indication indicating a firstlocation, in the first channel segment 410, of the first primary channeland ii) a second primary channel indication indicating a secondlocation, in the second channel segment 420, of the second primarychannel.

FIG. 4B is a diagram of the operating channel 400 at a second time,according to an embodiment. At the second time, the primary channel ofthe operating channel 400 has been changed to a different componentchannel. In an embodiment, for example, the AP 114 designates a secondcomponent channel that was previously designated as a secondary channel(e.g., secondary channel 424-2) as a second primary channel 472 anddesignates the first primary channel 412 as a secondary channel 474. Inan embodiment, for example, the AP 114 utilizes the first primarychannel 412 for at least one of transmitting or receiving MPDUs via thefirst component channel, before designating the second component channelas the second primary channel 472. In an embodiment, when designating acomponent channel as a primary channel, the AP 114 creates orinitializes one or more backoff timers (e.g., backoff timers 127) forthe component channel. In an embodiment, when designating a componentchannel as a secondary channel, the AP 114 removes or suspends one ormore backoff timers. Although the second primary channel 472 is locatedin the second segment 420 in the embodiment shown in FIG. 4B, in otherembodiments, the second primary channel is located in the first segment410 (e.g., at secondary channel 414-3).

In an embodiment, legacy client stations that conform to the legacyprotocol do not support an operating channel in multiple channelsegments or with multiple primary channels. In some embodiments, tofacilitate interoperability of the AP 114 with legacy client stations,the first communication protocol does not permit multiple primarychannels in an AP operating channel when the AP operating channel isalso supported by the legacy protocol. Accordingly, in an embodiment,the AP 114 is configured to operate with an AP operating channel thatincludes a single primary channel when the operating channel is alsopermitted by the legacy protocol, and to operate with an AP operatingchannel that includes multiple primary channels when the operatingchannel is not permitted by the legacy protocol.

In some embodiments, an operating channel of a client station (e.g., theclient station 154-1) has a bandwidth that is narrower than a bandwidthof an operating channel of the AP 114. In an embodiment, a clientstation 154 (e.g., the client station 154-1) operating with an operatingchannel that is narrower than an operating channel of the AP 114 ispermitted to operate at any location within the operating channel of theAP 114. For example, the client station 154-1 is permitted to operatewith an operating channel that does not cover a primary channel of theAP 114. In another embodiment, the client station 154 (e.g., the clientstation 154-1) operating with an operating channel that is narrower thanan operating channel of the AP 114 is not permitted to operate with anoperating channel that does not cover a primary channel of the AP 114.In this embodiment, an operating channel of the client station 154(e.g., the client station 154-1) that is narrower than an operatingchannel of the AP 114 operates at a location within the operatingchannel of the AP 114 that covers at least one primary channel of the AP114.

In the embodiment shown in FIG. 4B, the AP 114 changes from the firstprimary channel 412 (FIG. 4A) to the second primary channel 472 tosupport a legacy client station STA2 that has an operating channel thatonly includes the second primary channel 472 and the secondary channel424-1 in the second segment 420. In an embodiment, the AP 114 receivesan indication of the operating channel of the legacy client station STA2where the operating channel i) does not include any primary channel ofthe operating channel of the AP 114 and ii) spans multiple secondarychannels of the operating channel of the AP 114, and the AP 114 changesthe primary channel in response to the indication.

In some embodiments, the AP 114 provides an explicit indication of thechange in the primary channel to one or more client stations. In anembodiment, the AP 114 generates one or more MPDUs that include anexplicit indication of the designation of the second component channelas the primary channel 472. In this embodiment, the AP 114 transmits theMPDU using at least one of the first component channel and the secondcomponent channel. In other words, the AP 114 transmits the explicitindication via the first primary channel 412 (e.g., before or after thechange), via the second primary channel 472 (e.g., before or after thechange), or via both the first primary channel 412 and the secondprimary channel 472.

In an embodiment, the AP 114 generates a bandwidth indication of thebandwidth of the second primary channel 472 in the second segment 420that identifies the second component channel as the second primarychannel 472. In an embodiment, the AP 114 generates an MPDU thatincludes the bandwidth indication. In an embodiment, the bandwidthindication is a field within a MAC header of the MPDU. In anotherembodiment, the bandwidth indication is a field within a managementframe.

In some embodiments, the AP 114 provides an implicit indication of thechange in the primary channel to one or more client stations. In anembodiment, for example, the primary channel (e.g., one of the firstprimary channel 412 or the second primary channel 472) corresponds to aparticular predetermined time period. In various embodiments, thepredetermined time period is a service period, for example, a targetwake time (TWT) service period.

FIG. 5 is an example timing diagram 500 of a backoff timersynchronization after a primary channel change in an operating channel502, in an embodiment. In an embodiment, the operating channel 502corresponds to an operating channel of the AP 114, or of a basic serviceset (BSS) supported by the AP 114. In an embodiment, the operatingchannel 502 corresponds to an operating channel of a client station 154(e.g., the client station 154-1). In other embodiments, the operatingchannel 502 is employed by a communication device (e.g., an AP or aclient station) in a suitable communication network different from theWLAN 110.

The operating channel 502 is similar to the operating channel 400, butincludes four component channels. Although the component channels areshown as being contiguous, in other embodiments, one or more of thecomponent channels are located in different frequency bands and/or areseparated by a frequency gap, as described above. In the embodimentshown in FIG. 5 , the AP 114 changes the primary channel of theoperating channel 502 at a time t0 and at a time t1, which correspond tostart times of a first service period 510 and a second service period520, respectively. In other embodiments, the AP 114 changes the primarychannel at a different suitable time, for example, in response to anMPDU or PPDU from a client station.

In an embodiment, the first and second service periods 510 and 520correspond to different TWT service periods. During the first serviceperiod 510, the AP 114 designates a first component channel as a primarychannel 512 and remaining component channels as secondary channels514-1, 514-2, and 514-3. During the second service period 520, the AP114 designates a second component channel (i.e., the secondary channel514-1) as a primary channel 522 and designates the remaining componentchannels as secondary channels 524-1, 524-2, and 524-3. Accordingly, thefirst primary channel 512 is re-designated as a secondary channel 524-3.

Before transmitting MPDUs via the operating channel 502, the AP 114performs a backoff procedure that includes waiting for an expiration ofa backoff timer that corresponds to the primary channel. When theprimary channel is changed (e.g., from the primary channel 512 to 522),the AP 114 synchronizes a backoff timer 516, which corresponds to thecomponent channel that is the new primary channel, with other devicesthat use the component channel, in various embodiments. In anembodiment, for example, the AP 114 starts a network allocation vector(NAV) synchronization timer 515 and starts the backoff timer 516 afterexpiration of the NAV synchronization timer 515. In an embodiment, thebackoff timer 516 is a NAV. In an embodiment, the NAV synchronizationtimer 515 and the NAV 516 correspond to the multi-band backoff timers127 (FIG. 1 ). When starting the second service period 520 at the timet1, the AP 114 starts a NAV synchronization timer 525 and starts abackoff timer 526 after expiration of the NAV synchronization timer 525,where the NAV synchronization timer 525 and backoff timer 526 correspondto the second primary channel 522.

During the NAV synchronization timers 515 and 525, (i.e., while thetimers run and before their respective expirations), the AP 114 monitorsthe medium of the primary channel for transmissions by othercommunication devices. In an embodiment, when the AP 114 does notreceive or detect a frame in the medium before the NAV synchronizationtimer expires (e.g., becomes “0”), the AP starts the backoff timer 516.In the embodiment shown in FIG. 5 , the AP 114 transmits a PPDU 517after expiration of the backoff timer 516. When the AP 114 receives ordetects a frame (e.g., MPDU 521) in the medium before the NAVsynchronization timer expires, the AP 114 synchronizes the backoff timer526 using the detected frame. In an embodiment, for example, the AP 114receives the MPDU 521 that includes a NAV indication via the primarychannel 522 during the NAV synchronization timer 525, stops the NAVsynchronization timer 525, and sets the backoff timer 526 using the NAVindication. In an embodiment, the NAV indication is a high efficiency(HE) physical layer (PHY) header that includes a duration field. Inanother embodiment, the NAV indication is included in a suitable fieldof a PHY header or MAC header that corresponds to the MPDU receivedduring the NAV synchronization timer 525.

In various embodiments, the backoff timers 516 and 526 are set based ona group of respective backoff parameters, for example, for each accesscategory (AC) (i.e., one of AC_BE (best effort), AC_BK (background),AC_VI (video), AC_VO (voice)), there is a backoff timer (e.g., aninstance of the backoff timer 516 or 526), a contention window CW, acontention window minimum (CWmin), a contention window maximum (CWmax),a slot time, an arbitrary inter-frame space number (AIFSN), a quality ofservice short retry counter (QSRC), and a quality of service long retrycounter (QLRC). In an embodiment, the AP 114 is configured to set thebackoff parameters for the backoff timers 516 and 526 to values thatcorrespond to a successful frame exchange (e.g., setting a contentionwindow value to CWmin). In another embodiment, the AP 114 is configuredto set the backoff parameters to values that correspond to a serviceperiod (i.e., using values corresponding to service period 520 forbackoff timer 526). In yet another embodiment, the AP 114 is configuredset the backoff parameters to values that correspond to the priorprimary channel (i.e., using values corresponding to backoff timer 516for the backoff timer 526).

FIG. 6A and FIG. 6B are example timing diagrams 600 and 650 for a WLANcommunication device configured to use separate groups of backofftimers, i.e. one group of backoff timers (backoff timers for AC_BE,AC_BK, AC_VI, AC_VO), for each primary channel in multiple componentchannels of a WLAN communication channel 602 with multiple primarychannels, in an embodiment. In an embodiment, the operating channel 602corresponds to an operating channel of the AP 114, or of a basic serviceset (BSS) supported by the AP 114. In an embodiment, the operatingchannel 602 corresponds to an operating channel of a client station 154(e.g., the client station 154-1). In other embodiments, the operatingchannel 602 is employed by a communication device (e.g., an AP or aclient station) in a suitable communication network different from theWLAN 110. The operating channel 602 is similar to the operating channel400 and operating channel 500, but includes four component channels Ch0,Ch1, Ch2, and Ch3 and has multiple primary channels at the same time(i.e., Ch0 and Ch3). Although the component channels are shown as beingcontiguous, in other embodiments, one or more of the component channelsare located in different frequency bands with one (or more) primarychannel in each band and/or are separated by a frequency gap, asdescribed above. In an embodiment, for example, the component channelsCh0 and Ch1 are located in a channel segment within a 5 GHz band and thecomponent channels Ch2 and Ch3 are located in a channel segment within a6 GHz band.

In some embodiments, the AP 114 (or a client station 154) is configuredto use multiple primary channels over the operating channel 602 whereeach primary channel corresponds to its own group of backoff timers(backoff timers for AC_BE, AC_BK, AC_VI, AC_VO). In the embodiment shownin FIG. 6A, the AP 114 designates component channels Ch0 and Ch3 asprimary channels over the operating channel 602, corresponding tobackoff timers 606 and 636, respectively, and designates componentchannels Ch1 and Ch2 as secondary channels. In other embodiments, the AP114 uses additional or fewer primary channels over a different suitableoperating channel.

In an embodiment, the AP 114 checks an idle/busy status of other primarychannels and secondary channels, for example, component channel Ch3(primary) and component channels Ch1 and Ch2 (secondary), when thebackoff timer 606 expires before performing a transmission. When one ormore other component channels are idle within a suitable time period(e.g., a point control function interframe space, distributed controlfunction interframe space) before the backoff timer 516 expires, the AP114 performs, schedules, or triggers an uplink or downlink transmissionin the one or more idle component channels. In some embodiments, thebackoff timers of any band can be used for the backoff of simultaneoustransmission of multiple bands (channel segments). In some embodiments,the backoff timers of a specific channel segment can be used for thebackoff of simultaneous transmission of multiple bands (channelsegments), while the backoff timers of another channel segment can onlybe used for the transmission of the channel segment. In an embodiment,the channel segment can be a dedicated channel segment or a channelsegment having a lower load compared to other channel segments. In someembodiments, the backoff timers of a channel segment being used for thebackoff of simultaneous transmission of multiple bands (channelsegments) are toggled backoff timers of the channel segments. In otherwords, when the backoff timer of the channel segment1 is used for asimultaneous transmission via channel segment1 and channel segment2,then the backoff timer of the channel segment2 is used for a nextsimultaneous transmission of multiple channel segments. In someembodiments, when a channel segment whose backoff timer is not 0 is usedfor a simultaneous transmission, the backoff timer of the channelsegment will be increased by a random or pseudo-random value, forexample, per the current CW. In some embodiments, when the backoff timerof a primary channel related to a channel segment becomes 0, the channelsegment is combined with other channel segments whose backoff timersbecome 0. In an embodiment, for a channel segment with backoff timerbeing 0, the corresponding secondary channels that are idle are used forthe simultaneous transmission. In some embodiments, when a channelsegment whose backoff timer becomes 0, the AP 114 waits until thebackoff timer of another channel segment becomes zero for a simultaneoustransmission.

In some embodiments, the AP 114 utilizes only those idle componentchannels that satisfy corresponding channel bounding rules fortransmission. In the embodiment shown in FIG. 6A, the AP 114 determinesthat component channel Ch2 is busy, component channels Ch0, Ch1, and Ch3are idle, but that channel bounding rules do not allow for a puncturedPPDU. In this embodiment, the AP 114 transmits an unpunctured downlinkPPDU 640 and receives an unpunctured uplink PPDU 642 that utilize onlythe component channels Ch0 and Ch1. After the exchange of the PPDUs 640and 642, the AP 114 sets the contention window for both the backofftimer 606 and the backoff timer 636 to CWmin to indicate a successfulframe exchange.

In the embodiment shown in FIG. 6B, the AP 114 determines that componentchannel Ch2 is busy, component channels Ch0, Ch1, and Ch3 are idle, andthat channel bounding rules allow for a punctured PPDU. In thisembodiment, the AP 114 transmits a punctured downlink PPDU 690 andreceives an unpunctured uplink PPDU 692 that utilize the componentchannels Ch0, Ch1, and Ch3. After the exchange of the PPDUs 690 and 692,the AP 114 sets the contention window for both the backoff timer 606 andthe backoff timer 636 to CWmin to indicate a successful frame exchange.

FIG. 7 is an example timing diagrams 700 for a WLAN communication deviceconfigured to use separate sets of backoff timers (i.e. one set ofbackoff timers for AC_BE, AC_BK, QC_VI, QC_VO) in multiple componentprimary channels of a WLAN communication channel 702, in an embodiment.In an embodiment, the operating channel 702 corresponds to an operatingchannel of the AP 114, or of a basic service set (BSS) supported by theAP 114. In an embodiment, the operating channel 702 corresponds to anoperating channel of a client station 154 (e.g., the client station154-1). In other embodiments, the operating channel 702 is employed by acommunication device (e.g., an AP or a client station) in a suitablecommunication network different from the WLAN 110. The operating channel702 is similar to the operating channel 600 and includes four componentchannels Ch0, Ch1, Ch2, and Ch3. Although the component channels areshown as being contiguous, in other embodiments, one or more of thecomponent channels are located in different frequency bands and/or areseparated by a frequency gap, as described above.

In some embodiments, the AP 114 (or a client station 154) is configuredto use multiple primary channels over the operating channel 702 whereeach primary channel corresponds to its own set of backoff timers (i.e.backoff timers for AC_BE, AC_BK, AC_VI, AC_VO). In the embodiment shownin FIG. 7 , the AP 114 designates component channels Ch0 and Ch1 asprimary channels over the operating channel 702, corresponding tobackoff timers 706 and 716, respectively, and designates componentchannels Ch2 and Ch3 as secondary channels. In other embodiments, the AP114 uses additional or fewer primary channels over a different suitableoperating channel.

In some embodiments, the AP 114 is configured to set backoff parametersof a primary channel whose backoff timer expires to values according toEnhanced Distributed Control Function Channel Access (EDCA) backoffrules without adjusting the backoff timers of other primary channels. Inthe embodiment shown in FIG. 7 , the AP 114 determines, after expirationof the backoff timer 706-1, that component channels Ch0 and Ch1 of theoperating channel 702 are idle. The AP 114 performs a frame exchangethat includes a downlink PPDU 720 and an uplink PPDU 722 after theexpiration. In an embodiment, after the successful frame exchange, theAP 114 i) sets the backoff parameters that correspond to the backofftimer 706 to values corresponding to the successful frame exchange, forexample, by setting the contention window to CWmin, and ii) does notchange the backoff parameters that correspond to the backoff timer 716.On the other hand, the AP 114 determines, after expiration of thebackoff timer 706-2, that component channels Ch0 and Ch1 of theoperating channel 702 are idle and performs a frame exchange thatincludes a downlink PPDU 750 that has a collision 752 or other frameexchange failure. In an embodiment, after the failed frame exchange, theAP 114 i) sets the backoff parameters that correspond to the backofftimer 706 to values corresponding to an unsuccessful frame exchange, forexample, by doubling the contention window and increasing the QLRC, andii) does not change the backoff parameters that correspond to thebackoff timer 716.

In some embodiments, the AP 114 is configured to set backoff parametersof i) a primary channel whose backoff timer expires, and ii) otherprimary channels, to values according to Enhanced Distributed ControlFunction Channel Access (EDCA) backoff rules. In an embodiment, afterthe successful frame exchange, the AP 114 i) sets the backoff parametersthat correspond to the backoff timer 706 and backoff timer 716 to valuescorresponding to the successful frame exchange. In an embodiment, afterthe failed frame exchange, the AP 114 i) sets the backoff parametersthat correspond to the backoff timer 706 and the backoff timer 716 tovalues corresponding to an unsuccessful frame exchange.

FIG. 8 is an example timing diagram 800 for a WLAN communication deviceconfigured to suspend a backoff timer, in an embodiment. In anembodiment, the operating channel 802 corresponds to an operatingchannel of the AP 114, or of a basic service set (BSS) supported by theAP 114. In an embodiment, the operating channel 802 corresponds to anoperating channel of a client station 154 (e.g., the client station154-1). In other embodiments, the operating channel 802 is employed by acommunication device (e.g., an AP or a client station) in a suitablecommunication network different from the WLAN 110. The operating channel802 is similar to the operating channel 600 and includes four componentchannels Ch0, Ch1, Ch2, and Ch3. Although the component channels areshown as being contiguous, in other embodiments, one or more of thecomponent channels are located in different frequency bands and/or areseparated by a frequency gap, as described above.

In some embodiments, when a transmission opportunity (TXOP) holder(e.g., the AP 114 or a client station 154) of a TXOP utilizes a portionof the operating channel 802, the AP 114 suspends the backoff timers inother primary channels of the operating channel 802 during the TXOP. Inan embodiment, for example, when the AP 114 is not configured totransmit in a first primary channel while simultaneously transmitting ina second primary channel, the AP 114 suspends the backoff timer for thefirst primary channel while utilizing the second primary channel. In anembodiment, a WLAN communication device announces whether it can receiveframes in one band while it is receiving frames in another band. In theembodiment shown in FIG. 8 , the backoff timer 806 that corresponds toprimary channel Ch0 expires and the AP 114 performs a frame exchangeduring a TXOP 810. In this embodiment, the AP 114 suspends the backofftimer 836 that corresponds to the primary channel Ch3 during the TXOP810. The AP 114 resumes the backoff timer 836 when utilization of thecomponent channel Ch0 has completed.

Similarly, in some embodiments, when a TXOP responder (e.g., the AP 114or a client station 154) utilizes a portion of the operating channel802, the AP 114 suspends the backoff timers in other primary channels ofthe operating channel 802 during the TXOP. In an embodiment, forexample, when the AP 114 is not configured to transmit in a firstprimary channel while simultaneously receiving in a second primarychannel, the AP 114 suspends the backoff timer for the first primarychannel while utilizing the second primary channel. In an embodiment, aWLAN communication device announces whether it can receive frames in oneband while it is transmitting frames in another band.

In some embodiments, the AP 114 is configured to determine whether afirst component channel and a second component channel aresimultaneously usable before suspending a corresponding backoff timer.In some embodiments, for example, the first and second componentchannels are simultaneously usable when they are located in differentbands (i.e., a 2.4 GHz band and a 5 GHz band) and/or handled bydifferent RF radios. In some embodiments, the first and second componentchannels are not simultaneously usable when they are located in adjacentbands (e.g., 5 GHz band and 6 GHz band).

FIG. 9 is an example timing diagram 900 for a WLAN communication deviceconfigured to simultaneously utilize multiple primary channels, in anembodiment. In an embodiment, the operating channel 902 corresponds toan operating channel of the AP 114, or of a basic service set (BSS)supported by the AP 114. In an embodiment, the operating channel 902corresponds to an operating channel of a client station 154 (e.g., theclient station 154-1). In other embodiments, the operating channel 902is employed by a communication device (e.g., an AP or a client station)in a suitable communication network different from the WLAN 110. Theoperating channel 902 is similar to the operating channel 600 andincludes four component channels Ch0, Ch1, Ch2, and Ch3. Although thecomponent channels are shown as being contiguous, in other embodiments,one or more of the component channels are located in different frequencybands and/or are separated by a frequency gap, as described above.

As described above, in some embodiments, the AP 114 (or a client station154) is able to simultaneously utilize different primary channels, forexample, when the primary channels are located in different bands. Inthe embodiment shown in FIG. 9 , the AP 114 is configured tosimultaneously utilize primary channels Ch0 and Ch3. In this embodiment,the AP 114 does not suspend the backoff timer 936 that corresponds tothe primary channel Ch3 while utilizing the primary channel Ch0 andsecondary channel Ch1. In other words, when it is determined that afirst component channel and a second component channel aresimultaneously usable, the AP 114 utilizes the second component channelasynchronously with the first component channel. In the embodiment shownin FIG. 9 , the backoff timer 936 i) is not suspended during a TXOP 910,and ii) expires during the TXOP 910, allowing the AP 114 to perform atransmission 952 during the TXOP 910 using a different primary channelCh3.

FIG. 10 is a flow diagram illustrating an example method 1000 foroperation of a first communication device in a WLAN communicationchannel between the first communication device and one or more secondcommunication devices, according to an embodiment. The WLANcommunication channel includes a plurality of component channels, forexample, component channels as described above and shown in FIGS. 4A,4B, 5, 6A, 6B, 7, 8, and 9 . In an embodiment, the method 1000 isimplemented by a client station in the WLAN, according to an embodiment.With reference to FIG. 1 , the method 1000 is implemented by the networkinterface 162, in an embodiment. For example, in one such embodiment,the PHY processor 170 is configured to implement the method 1000.According to another embodiment, the MAC processor 166 is alsoconfigured to implement at least a part of the method 1000. Withcontinued reference to FIG. 1 , in yet another embodiment, the method1000 is implemented by the network interface 122 (e.g., the PHYprocessor 130 and/or the MAC processor 126). In other embodiments, themethod 1000 is implemented by other suitable network interfaces.

At block 1002, the AP 114 designates i) a first component channel of theplurality of component channels as a first primary channel, and ii) asecond component channel of the plurality of component channels as asecond primary channel. In an embodiment, for example, the AP 114designates the component channels Ch0 and Ch3 shown in FIG. 8 as primarychannels. In an embodiment, the first component channel and the secondcomponent channel are non-contiguous. In an embodiment, for example, thefirst component channel is separated from the second component channelby at least one third component channel. In another embodiment, thefirst component channel is located in a different band from the secondcomponent channel.

In an embodiment, the WLAN communication channel has i) a first radiofrequency (RF) channel segment that occupies a first frequency bandwidthand includes at least the first component channel, ii) a second RFchannel segment that occupies a second frequency bandwidth and includesat least the second component channel, and the first frequency bandwidthand the second frequency bandwidth do not overlap and are separated by afrequency gap. In an embodiment, for example, the first RF channelsegment and the second RF channel segment correspond to the channelsegments 410 and 420 as described above with respect to FIGS. 4A and 4B.In an embodiment, the first communication device includes i) a first RFradio configured for operation in the first RF channel segment and notin the second RF channel segment and ii) a second RF radio configuredfor operation in the second RF channel segment and not the first RFchannel segment. In an embodiment, for example, the first RF radiocorresponds to the RF radio 328 and the second RF radio corresponds tothe RF radio 336.

At block 1004, the AP 114 suspends a backoff timer that corresponds tothe second component channel while utilizing the first component channeland without utilizing the second component channel. In an embodiment,for example, the AP 114 suspends the backoff timer 836 without utilizingthe component channel Ch3 (FIG. 8 ). In an embodiment, utilization ofthe first component channel includes at least one of transmitting orreceiving media access layer protocol data units (MPDUs). In anembodiment, for example, the utilization includes transmission of theA-MPDU and reception of the block acknowledgment during the TXOP 810(FIG. 8 ).

At block 1006, the AP 114 resumes the backoff timer when utilization ofthe first component channel has completed. In an embodiment, forexample, the AP 114 resumes the backoff timer 836 after the TXOP 810.

FIG. 11 is a flow diagram illustrating an example method 1100 foroperation of a first communication device in a WLAN communicationchannel between the first communication device and one or more secondcommunication devices, according to an embodiment. The WLANcommunication channel includes a plurality of component channels, forexample, component channels as described above and shown in FIGS. 4A,4B, 5, 6A, 6B, 7, 8, and 9 . In an embodiment, the method 1100 isimplemented by a client station in the WLAN, according to an embodiment.With reference to FIG. 1 , the method 1100 is implemented by the networkinterface 162, in an embodiment. For example, in one such embodiment,the PHY processor 170 is configured to implement the method 1100.According to another embodiment, the MAC processor 166 is alsoconfigured to implement at least a part of the method 1100. Withcontinued reference to FIG. 1 , in yet another embodiment, the method1100 is implemented by the network interface 122 (e.g., the PHYprocessor 130 and/or the MAC processor 126). In other embodiments, themethod 1100 is implemented by other suitable network interfaces.

At block 1102, the AP 114 designates i) a first component channel of theplurality of component channels as a first primary channel, and ii) asecond component channel of the plurality of component channels as asecond primary channel. In an embodiment, for example, the AP 114designates the component channels Ch0 and Ch3 shown in FIG. 8 as primarychannels.

At block 1104, the AP 114 determines whether the first component channeland the second component channel are simultaneously usable by the firstcommunication device. In an embodiment, for example, the AP 114determines whether the first component channel and the second componentchannel are handled by different RF radios.

At block 1106, when it is determined that the first component channeland the second component channel are not simultaneously usable by thefirst communication device, the AP 114 suspends a backoff timer thatcorresponds to the second component channel while the firstcommunication device utilizes the first component channel, whereutilization of the first component channel includes at least one oftransmitting or receiving a media access control protocol data units(MPDUs) via the first component channel. In an embodiment, for example,the AP 114 suspends the backoff timer 836 without utilizing thecomponent channel Ch3 (FIG. 8 ). In an embodiment, utilization of thesecond component channel includes at least one of transmitting orreceiving MPDUs via the second component channel.

At block 1108, when it is determined that the first component channeland the second component channel are simultaneously usable by the firstcommunication device, the AP 114 utilizes the second component channelasynchronously with the first component channel.

In an embodiment, the AP 114 resumes the backoff timer when utilizationof the first component channel by the first communication device hascompleted. In an embodiment, for example, the AP 114 resumes the backofftimer 836 after the TXOP 810.

FIG. 12 is a flow diagram illustrating an example method 1200 foroperation of a first communication device in a WLAN communicationchannel between the first communication device and one or more secondcommunication devices, according to an embodiment. The WLANcommunication channel includes a plurality of component channels, forexample, component channels as described above and shown in FIGS. 4A,4B, 5, 6A, 6B, 7, 8, and 9 . In an embodiment, the method 1200 isimplemented by a client station in the WLAN, according to an embodiment.With reference to FIG. 1 , the method 1200 is implemented by the networkinterface 162, in an embodiment. For example, in one such embodiment,the PHY processor 170 is configured to implement the method 1200.According to another embodiment, the MAC processor 166 is alsoconfigured to implement at least a part of the method 1200. Withcontinued reference to FIG. 1 , in yet another embodiment, the method1200 is implemented by the network interface 122 (e.g., the PHYprocessor 130 and/or the MAC processor 126). In other embodiments, themethod 1200 is implemented by other suitable network interfaces.

At block 1202, the AP designates i) a first component channel of theplurality of component channels as a primary channel of the WLANcommunication channel, and ii) a second component channel of theplurality of component channels as a secondary channel of the WLANcommunication channel. In an embodiment, for example, the AP 114designates the component channel 412 (FIG. 4 ) as a primary channel anddesignates the component channel 424-2 as a secondary channel. Inanother embodiment, for example, the AP 114 designates the componentchannel Ch0 (FIG. 5 ) as a primary channel 512 and designates thecomponent channel Ch3 as a secondary channel 514-1.

At block 1204, the AP 114 utilizes the first component channel as theprimary channel for at least one of transmitting or receiving mediaaccess control protocol data units (MPDUs) via the first componentchannel. In an embodiment, for example, the AP 114 transmits the PPDU517 (FIG. 5 ).

At block 1206, the AP 114 designates i) the first component channel as asecondary channel of the WLAN communication channel, and ii) the secondcomponent channel as the primary channel of the WLAN communicationchannel. In an embodiment, for example, the AP 114 designates thecomponent channel Ch0 as a secondary channel 524 and designates thecomponent channel Ch3 as a primary channel 522.

At block 1208, the AP 114 utilizes the second component channel as theprimary channel for at least one of transmitting or receiving MPDUs viathe second component channel. In an embodiment, for example, the AP 114transmits the PPDU 527 (FIG. 5 ).

In an embodiment, the AP 114 starts a network allocation vector (NAV)synchronization timer after designating the second component channel asthe primary channel, and starts a backoff timer after expiration of theNAV synchronization timer, where utilizing the second component channelincludes before utilizing the second component channel as the primarychannel after expiration of the backoff timer. In an embodiment, the AP114 starts the NAV synchronization timer 515 and starts the backofftimer 516, as described above with respect to FIG. 5 .

In an embodiment, the AP 114 receives an MPDU that includes a NAVindication via the second component channel during the NAVsynchronization timer and i) stops the NAV synchronization timer, andii) sets a NAV that corresponds to the second component channel usingthe NAV indication. In an embodiment, for example, the AP 114 receivesthe MPDU 521, stops the NAV synchronization timer 525, and sets thebackoff timer 526 using the NAV indication of the MPDU 521, as describedabove with respect to FIG. 5 . In an embodiment, the NAV indication is ahigh efficiency (HE) physical layer (PHY) header that includes aduration field.

In an embodiment, the AP 114 sets one or more backoff parameters thatcorrespond to the backoff timer to respective values that correspond toa successful frame exchange. In another embodiment, the AP sets one ormore backoff parameters that correspond to the backoff timer torespective values that correspond to a service period. In yet anotherembodiment, the AP 114 sets one or more backoff parameters thatcorrespond to the backoff timer to respective values that correspond tothe first component channel. In an embodiment, for example, the AP 114sets the backoff parameters as described above with respect to FIG. 7 .

In an embodiment, the AP 114 generates one or more MPDUs that include anexplicit indication of the designation of the second component channelas the primary channel. The AP 114 transmits the one or more MPDUs usingat least one of the first component channel and the second componentchannel.

In an embodiment, the AP 114 utilizes the first component channel as theprimary channel during a first predetermined time period and utilizesthe second component channel as the primary channel during a secondpredetermined time period that does not overlap with the firstpredetermined time period. In an embodiment, for example, the AP 114utilizes the component channel Ch0 as the first primary channel 512during the service period 510 and utilizes the component channel Ch3 asthe second primary channel 522 during the service period 520, asdescribed above with respect to FIG. 5 . In an embodiment, the firstpredetermined time period corresponds to a first service period and thesecond predetermined time period corresponds to a second service period.

In an embodiment, the WLAN communication channel has i) a first RFchannel segment that occupies a first frequency bandwidth and includesat least the first component channel, ii) a second RF channel segmentthat occupies a second frequency bandwidth and includes at least thesecond component channel. The first frequency bandwidth and the secondfrequency bandwidth do not overlap and are separated by a frequency gap.In an embodiment, for example, the first RF channel segment and thesecond RF channel segment correspond to the channel segments 410 and 420as described above with respect to FIGS. 4A and 4B.

At least some of the various blocks, operations, and techniquesdescribed above may be implemented utilizing hardware, a processorexecuting firmware instructions, a processor executing softwareinstructions, or any combination thereof. When implemented utilizing aprocessor executing software or firmware instructions, the software orfirmware instructions may be stored in any computer readable memory suchas on a magnetic disk, an optical disk, or other storage medium, in aRAM or ROM or flash memory, processor, hard disk drive, optical diskdrive, tape drive, etc. The software or firmware instructions mayinclude machine readable instructions that, when executed by one or moreprocessors, cause the one or more processors to perform various acts.

When implemented in hardware, the hardware may comprise one or more ofdiscrete components, an integrated circuit, an application-specificintegrated circuit (ASIC), a programmable logic device (PLD), etc.

While the present invention has been described with reference tospecific examples, which are intended to be illustrative only and not tobe limiting of the invention, changes, additions and/or deletions may bemade to the disclosed embodiments without departing from the scope ofthe invention.

What is claimed is:
 1. A method for simultaneously transmitting via aplurality of channel segments that includes i) a first channel segmentin a first radio frequency (RF) band, and ii) a second channel segmentin a second RF band, the method comprising: maintaining, at acommunication device, a first backoff timer that corresponds to thefirst channel segment, the first backoff timer for determining when thecommunication device can transmit via the first channel segment;maintaining, at the communication device, a second backoff timer thatcorresponds to the second channel segment, the second backoff timer fordetermining when the communication device can transmit via the secondchannel segment; in response to the first backoff timer expiring,waiting, by the communication device, to transmit via the first channelsegment until the second backoff timer expires; and after waiting totransmit via the first channel segment and in response to the secondbackoff timer expiring: transmitting, by the communication device, viathe first channel segment beginning at a start time, and transmitting,by the communication device, via the second channel segment beginning atthe start time.
 2. The method of claim 1, wherein transmitting via thefirst channel segment and transmitting via the second channel segmentcomprises: simultaneously transmitting with a gap in frequency betweenthe first channel segment and the second channel segment.
 3. The methodof claim 1, wherein transmitting via the first channel segment andtransmitting via the second channel segment comprises: endingtransmission via the first channel segment at an end time; and endingtransmission via the second channel segment at the end time.
 4. Themethod of claim 1, wherein transmitting via the first channel segmentand transmitting via the second channel segment comprises: transmittingvia the first channel segment with a first RF radio configured foroperation in the first RF band; and transmitting via the second channelsegment with a second RF radio configured for operation in the second RFband.
 5. The method of claim 4, wherein transmitting via the firstchannel segment and transmitting via the second channel segment furthercomprises: generating, by a first baseband signal processor coupled tothe first RF radio, a first baseband signal corresponding to a first RFtransmission via the first channel segment; and generating, by a secondbaseband signal processor coupled to the second RF radio, a secondbaseband signal corresponding to a second RF transmission via the secondchannel segment.
 6. The method of claim 1, wherein: the first channelsegment comprises a first primary channel and one or more firstsecondary channels; the second channel segment comprises a secondprimary channel and one or more second secondary channels; maintainingthe first backoff timer comprises maintaining the first backoff timer tocorrespond with the first primary channel; and maintaining the secondbackoff timer comprises maintaining the second backoff timer tocorrespond with the second primary channel.
 7. The method of claim 1,further comprising: maintaining, at the communication device, a networkallocation vector (NAV) timer for monitoring use of a communicationmedium; wherein maintaining the first backoff timer comprises startingthe first backoff timer in response to the NAV timer expiring.
 8. Acommunication device, comprising: a wireless network interface devicethat is configured to communicate simultaneously via a plurality ofchannel segments having i) a first channel segment in a first radiofrequency (RF) band, and ii) a second channel segment in a second RFband, wherein the wireless network interface device comprises: one ormore integrated circuit (IC) devices, a first backoff timer thatcorresponds to the first channel segment, the first backoff timerimplemented on the one or more IC devices, and a second backoff timerthat corresponds to the second channel segment, the second backoff timerimplemented on the one or more IC devices; wherein the one or more ICdevices are configured to: maintain the first backoff timer to determinewhen the communication device can transmit via the first channelsegment, maintain the second backoff timer to determine when thecommunication device can transmit via the second channel segment, inresponse to the first backoff timer expiring, control the wirelessnetwork interface device to wait to transmit via the first channelsegment until the second backoff timer expires, and after controllingthe wireless network interface device to wait to transmit via the firstchannel segment and in response to the second backoff timer expiring:control the wireless network interface device to transmit via the firstchannel segment beginning at a start time, and control the wirelessnetwork interface device to transmit via the second channel segmentbeginning at the start time.
 9. The communication device of claim 8,wherein the one or more IC devices are configured to control thewireless network interface device to, as part of controlling thewireless network interface device to transmit via the first channelsegment and to transmit via the second channel segment: end transmissionvia the first channel segment at an end time; and end transmission viathe second channel segment at the end time.
 10. The communication deviceof claim 8, wherein the wireless network interface device furthercomprises: a first RF radio configured for operation in the first RFband; and a second RF radio configured for operation in the second RFband; wherein the one or more IC devices are configured to, as part ofcontrolling the wireless network interface device to transmit via thefirst channel segment and to transmit via the second channel segment:control the first RF radio to transmit via the first channel segment,and control the second RF radio to transmit via the second channelsegment.
 11. The communication device of claim 10, wherein the first RFradio and the second RF radio are configured to simultaneously transmitvia the first channel segment and transmit via the second channelsegment with a gap in frequency between the first channel segment andthe second channel segment.
 12. The communication device of claim 10,wherein the wireless network interface device further comprises: a firstbaseband signal processor implemented on the one or more IC devices, thefirst baseband signal processor coupled to the first RF radio; and asecond baseband signal processor implemented on the one or more ICdevices, the second baseband signal processor coupled to the second RFradio; wherein the first baseband signal processor is configured to, aspart of the one or more IC devices controlling the wireless networkinterface to transmit via the first channel segment: generate a firstbaseband signal corresponding to a first RF transmission via the firstchannel segment; and wherein the second baseband signal processor isconfigured to, as part of the one or more IC devices controlling thewireless network interface to transmit via the second channel segment:generate a second baseband signal corresponding to a second RFtransmission via the first channel segment.
 13. The communication deviceof claim 12, wherein the wireless network interface device furthercomprises: a medium access control (MAC) processor implemented on theone or more IC devices, the MAC processor coupled to the first basebandsignal processor and the second baseband signal processor.
 14. Thecommunication device of claim 8, wherein: the first channel segmentcomprises a first primary channel and one or more first secondarychannels; the second channel segment comprises a second primary channeland one or more second secondary channels; and the one or more ICdevices are configured to maintain the first backoff timer to correspondwith the first primary channel, and maintain the second backoff timer tocorrespond with the second primary channel.
 15. The communication deviceof claim 8, wherein: the wireless network interface device furthercomprises a network allocation vector (NAV) timer implemented on the oneor more IC devices; the one or more IC devices are further configuredto: maintain the NAV timer to monitor use of a communication medium, andstarting the first backoff timer in response to the NAV timer expiringas part of maintaining the first backoff timer.
 16. The communicationdevice of claim 8, wherein: the wireless network interface devicefurther comprises synchronization control circuitry implemented on theone or more IC devices; and the synchronization control circuitry isconfigured to: in response to the first backoff timer expiring, controlthe wireless network interface device to wait to transmit via the firstchannel segment until the second backoff timer expires, and aftercontrolling the wireless network interface device to wait to transmitvia the first channel segment and in response to the second backofftimer expiring: prompt the wireless network interface device to transmitvia the first channel segment beginning at a start time, and prompt thewireless network interface device to transmit via the second channelsegment beginning at the start time.
 17. The communication device ofclaim 8, wherein the wireless network interface device furthercomprises: a plurality of transceivers configured to simultaneouslytransmit via the first channel segment and the second channel segment.18. The communication device of claim 17, further comprising: aplurality of antennas coupled to the plurality of transceivers.
 19. Thecommunication device of claim 8, further comprising: a host processorcoupled to the wireless network interface device.